I have found those textures, and made the original seraphim hair white, but they are only for hair 1 and 2 and I would like to find the one for hair 3. I have also found hair 5 & 6 for seraphim, 3 & 4 are the only ones I havent seen.
EDIT: just noticed, seraphim hair 3 & 4 uses the sera_hair1 textures, so problem solved, I now have my white haired seraphim and is very happy